The basic principles of heat recovery in internal combustion engines are simple. Exhaust gases are high-temperature gases that are given off into the atmosphere wasting a large amount of energy. If these gases are passed through a heat exchanger, part of the heat is transferred to another fluid for being used in various applications and its energy is partially exploited. These applications include, mentioned by way of example, heating the vehicle interior or increasing the engine oil temperature at the moment of starting so that it reaches optimal lubrication conditions in the shortest time possible.
The passage of exhaust gases through the heat exchanger does not have to occur at all times, so the existence of a bypass valve that manages the passage of hot gas either through the heat exchanger or through the main conduit arranged in parallel with the heat exchanger and therefore without the interposition of the exchanger is necessary.
Bypass valves have a primary chamber which is in fluidic communication with one inlet and two outlets such that the position of an internal flap establishes if the fluid is diverted from the inlet to one outlet or to the other. The diversion of the flow in one direction or the other always entails a pressure loss.
When heat exchanger is used only on occasions because heat recovery is a function that is used only now and again, the pressure loss in the bypass valve penalizes the overall performance of the engine continuously even in the event that the heat recovery function is not used.
The present invention solves this technical problem as it is provided with a heat recovery device that almost introduces no loss and produces almost no modifications in the flow when the bypass valve is positioned such that the gas goes through the main conduit by closing and preventing passage through the heat exchanger. This technical problem is solved with a special configuration of the valve such that the main conduit has an internal configuration that is almost identical to the configuration that it would have without incorporating the heat recovery device, i.e., the flow path is virtually left unaffected by the incorporation of the heat recovery device.